Place oven rack in center and preheat to 350° F. Butter and flour a 9 x 5 x 3 inch loaf pan.
Used stand mixer to beat together butter and sugar, until light and fluffy. Add lemon zest. Mix in eggs, one at a time, until well combined. Mix in vanilla.
In separate bowl, sift together flour, baking soda, baking powder, and salt.
Add dry ingredients 1/2 at a time, alternating with sour cream. Mix until just combined.
Pour into prepared pan and spread out evenly. Bake about 1 hour, until a tested inserted in center comes out clean. Remove from oven to a rack, do not turn out of pan.